In a Long Term Evolution (“LTE”) system, an evolved base station (“eNB”) performs uplink and downlink data scheduling for a user equipment (“UE”) through a physical downlink control channel (“PDCCH”), where a minimum scheduling interval is one subframe, and a time duration of one subframe is 1 millisecond. A PDCCH used for the downlink data scheduling is referred to as a downlink assignment (DL_Assignment), and a PDCCH used for the uplink data scheduling is referred to as an uplink grant (UL_Grant). When a base station performs downlink data scheduling for a UE, channel state information (CSI) fed back by the UE is required. One CSI feedback manner in the LTE system is an aperiodic CSI feedback. Specifically, the aperiodic CSI feedback is triggered through an uplink grant UL_Grant, and the uplink grant UL_Grant notifies resources occupied by the aperiodic CSI.
However, when a data volume of downlink scheduling is large, dependence on the aperiodic CSI fed back by the UE may be strong. If there is no uplink data scheduling at the time, uplink grants UL_Grants are sent because the aperiodic CSI is required to be fed back, and therefore, there will be many uplink grants UL_Grants that schedule only the aperiodic CSI, thereby leading to an increase of PDCCH overhead.
Therefore, it is necessary to provide a corresponding technical solution that can trigger feedback of aperiodic CSI and reduce control channel overhead.